Helij
2
He
Skupina
18
Perioda
1
Blok
s
Protoni
Elektroni
Nevtroni
2
2
2
Splošne lastnosti
Vrstno število
2
Atomska teža
4,002602
Masno število
4
Kategorija
Žlahtni plini
Barva
Brezbarven
Radioaktivno
Ne
From the Greek word helios, the sun
Kristalna struktura
Ploskovno centrirana kubična
Zgodovina
French astronomer Jules Janssen obtained the first evidence of helium during the solar eclipse of 1868.
Norman Lockyer and Edward Frankland suggested the name helium for the new element.
In 1895, Sir William Ramsay discovered helium in the uranium mineral cleveite.
It was independently discovered in cleveite by Per Teodor Cleve and Abraham Langlet.
Norman Lockyer and Edward Frankland suggested the name helium for the new element.
In 1895, Sir William Ramsay discovered helium in the uranium mineral cleveite.
It was independently discovered in cleveite by Per Teodor Cleve and Abraham Langlet.
Elektroni po lupinah
2
Razporeditev elektronov
1s2
Unlike any other element, helium will remain liquid down to absolute zero at normal pressures
Fizikalne lastnosti
Faza snovi
Plin
Gostota
0,0001785 g/cm3
Tališče
0,95 K | -272,2 °C | -457,96 °F
Vrelišče
4,22 K | -268,93 °C | -452,07 °F
Talilna toplota
0,02 kJ/mol
Izparilna toplota
0,083 kJ/mol
Toplotna kapaciteta
5,193 J/g·K
Zastopanost v Zemljini skorji
5,5×10-7%
Zastopanost v vesolju
23%
CAS številka
7440-59-7
PubChem CID številka
23987
Atomske lastnosti
Atomski polmer
31 pm
Kovalentni polmer
28 pm
Elektronegativnost
-
Ionizacijski potencial
24,5874 eV
Atomski volumen
27,2 cm3/mol
Toplotna prevodnost
0,00152 W/cm·K
Oksidacijska stanja
0
Uporabe
Helium is used as a protective gas in growing silicon and germanium crystals, in titanium and zirconium production, and in gas chromatography.
Helium at low temperatures is used in cryogenics.
Helium is used for filling balloons and for pressurizing liquid fuel rockets.
Helium is used as a shielding gas in arc welding processes.
Helium at low temperatures is used in cryogenics.
Helium is used for filling balloons and for pressurizing liquid fuel rockets.
Helium is used as a shielding gas in arc welding processes.
Helium is not known to be toxic
Izotopi
Stabilni izotopi
3He, 4HeNestabilni izotopi
5He, 6He, 7He, 8He, 9He, 10He